Introduction of Arabidopsis's heat shock factor HsfA1d mitigates adverse effects of heat stress on potato (Solanum tuberosum L.) plant.

Thermal stress induces a wide array of morphological and physiological changes in potato affecting its development and economic yield. Response to thermal stress in plants is mostly regulated by heat shock factors (hsfs). The current study aimed at improving heat tolerance by transforming potato plant with heat shock factor, HsfA1d, using Agrobacterium. Gateway cloning strategy was adopted for isolation of HsfA1d from Arabidopsis thaliana and cloning into plant expression vector. The target gene was introduced into potato by infecting internodal explants with Agrobacterium strain GV3101 carrying pGWB402Ω-HsfA1d construct. Upon exposure to heat stress, the wild-type plants turned yellowish, whereas no phenotypic effect on transgenic plants was observed. Expression of HsfA1d in transgenic plants was increased by 5.8-fold under thermal stress compared to room temperature. Transgenic plants exhibited 6-fold increase in the expression of downstream HSP70 under thermal stress compared to wild-type plants. Both chlorophyll a and b were significantly decreased in wild-type plants while no such decrease was recorded in transgenic plants under thermal stress. Heat stress was found to have no significant effect on carotenoid pigments of both wild-type and transgenic plants. Significantly lower electrolyte leakage from transgenic plants was witnessed compared to wild type upon exposure to thermal stress. Transgenic plants accumulated significantly higher proline content compared to wild-type plants under heat stress. It is concluded that HsfA1d plays a vital role in plant thermotolerance and hence can be effectively used to enhance the resistance of crop plants against heat stress.

eEF2K inhibition blocks Aß42 neurotoxicity by promoting an NRF2 antioxidant response.

Soluble oligomers of amyloid-ß (Aß) impair synaptic plasticity, perturb neuronal energy homeostasis, and are implicated in Alzheimer's disease (AD) pathogenesis. Therefore, significant efforts in AD drug discovery research aim to prevent the formation of Aß oligomers or block their neurotoxicity. The eukaryotic elongation factor-2 kinase (eEF2K) plays a critical role in synaptic plasticity, and couples neurotransmission to local dendritic mRNA translation. Recent evidence indicates that Aß oligomers activate neuronal eEF2K, suggesting a potential link to Aß induced synaptic dysfunction. However, a detailed understanding of the role of eEF2K in AD pathogenesis, and therapeutic potential of eEF2K inhibition in AD, remain to be determined. Here, we show that eEF2K activity is increased in postmortem AD patient cortex and hippocampus, and in the hippocampus of aged transgenic AD mice. Furthermore, eEF2K inhibition using pharmacological or genetic approaches prevented the toxic effects of Aß42 oligomers on neuronal viability and dendrite formation in vitro. We also report that eEF2K inhibition promotes the nuclear factor erythroid 2-related factor (NRF2) antioxidant response in neuronal cells, which was crucial for the beneficial effects of eEF2K inhibition in neurons exposed to Aß42 oligomers. Accordingly, NRF2 knockdown or overexpression of the NRF2 inhibitor, Kelch-Like ECH-Associated Protein-1 (Keap1), significantly attenuated the neuroprotection associated with eEF2K inhibition. Finally, genetic deletion of the eEF2K ortholog efk-1 reduced oxidative stress, and improved chemotaxis and serotonin sensitivity in C. elegans expressing human Aß42 in neurons. Taken together, these findings highlight the potential utility of eEF2K inhibition to reduce Aß-mediated oxidative stress in AD.